Oval widening of the west side of the canal opposite the former entrance to the Black Park Collieries Railway Dock at the north end of the Chirk Cutting. The purpose of the winding hole was to allow boats to turn at right-angles to the canal line so that they could enter the Black Park Colliieries Dock, later used by the Glyn Valley Tramway and also known as Bottom Wharf.

Stephen R. Hughes, 29.05.2007.